Proline-rich proteins (pRPs) are the most abundant proteins in the saliva. Some of them have important tooth-related functions. By understanding their genetic determination, polymorphic varitions, development, and tissue expressions, we will understand more about their functions in health and disease. We will characterize genetic variations of salivary PRPs (from random samples and families) by electrophoretic analysis. We will relate the many PRPs to the six PRP "genes" as defined by DNA analysis. We will study the developmental changes of the many PRPs from the first day of life through three years of age using electrophoretic and protein detection techniques. We will prepare monoclonal antibodies to a variety of acidic and basic PRPs: to probe (with histochemical techniques) normal salivary and respiratory tract tissues and salivary gland tumors; to detect tissue, cellular and subcellular compartmentalization of different PRPs; to identify specific PRP cDNAs in expression libraries; and to study the genetic interrelationship of the variety of PRPs by immunoblotting techniques. We will study the PRP gene complex at the DNA level: to characterize, by restriction mapping and DNA sequencing, genes and cDNAs that code for PRPs; to match specific PRPs with their genes and cDNAs; to determine the linkage relationships of the PRP "genes"; to search for the molecular basis of unusual polymorphic expressions of PRPs as "null" allele and molecular size variants; to elucidate the molecular basis of DNA polymorphisms. We will study inheritance of PRP DNA and protein polymorhisms in families with gene blotting, labelled DNA probes, and salivary protein typing to look for linkage relationships and identification of protein variants with DNA polymorphisms. We will link by family studies other known chromosome 12 DNA markers with PRP genes. We will sublocalize (by study of backcrosses and RIS) PRP genes on chromosome 8 in the mouse with DNA probes to search for linkages to mouse genes that may have homologues on human chromosome 12. We will characterize specific chromosomal abnormalities in benign salivary mixed cell tumors and their derivative cell lines by cytogenetic (banding) techniques and probing the DNAs with specific DNA probes for chromosome 12 markers, since chromosome 12 abnormalities occur in thse tumors. We will clone and characterize, by DNA sequene analysis, genes and cDNAs for the salivry proteins statherin and the histidine-rich proteins and determine their chromosomal localizations. Thus, we hope to learn more about the biology and possible function of these unique salivary proteins.